Calpains are a ubiquitous, well-conserved family of calcium-dependent, cysteine proteases. Calpain families have been implicated in neurodegenerative processes, as their activation can be triggered by calcium influx and oxidative stress. Calpain I and II are heterodimeric with distinct large subunits associated with common small subunits, all of which are encoded by different genes. The small regulatory subunit consists of an N-terminal domain, containing about 30% glycine residues and a C-terminal Ca-binding domain. Two transcript variants encoding the same protein have been identified for this gene.
This gene encodes a small subunit common to both calpain I and II and is associated with myotonic dystrophy.
Elevated expression of Capn4 has been found to be associated with progression of various cancers such as hepatocellular and renal carcinoma.
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↑Zhuang Q, Qian X, Cao Y, Fan M, Xu X, He X (April 2014). "Capn4 mRNA level is correlated with tumour progression and clinical outcome in clear cell renal cell carcinoma". The Journal of International Medical Research. 42 (2): 282–91. doi:10.1177/0300060513505524. PMID24514433.
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